This invention relates to a shape measuring apparatus for eyeglasses which measures a lens shape of a lens for eyeglasses or an inner circumferential contour shape of a lens frame of eyeglasses.
A shape measuring apparatus for eyeglasses for measuring a contour shape of a pair of lens frames comprising an eyeglass frame, for example, is disclosed in Japanese patent publication number H07-290348 or H07-285057.
The shape measuring apparatus for eyeglasses has a holder which holds an eyeglass frame, a turning section which turns the holder around a rotating shaft provided in the shape measuring apparatus for eyeglasses, a measuring element which traces a groove portion formed inside of the pair of lens frames of the eyeglass frame, a driver which drives the measuring element, a position detector which detects a position of the measuring element, and a controlling-calculating section which controls the driver and obtains and processes position information of the measuring element by the position detector.
In the shape measuring apparatus for eyeglasses, in a state where the eyeglass frame is held by the holder, the controlling-calculating section controls the turning section such that a lens frame which is measured is in approximately a horizontal state when measuring, and controls the driver such that the measuring element slides on the groove portion of the lens frame, and thereby a three-dimensional shape of the lens frame is traced by the measuring element and the three-dimensional shape of the lens frame is obtained based on information of a driving state of the driver and position information of the measuring element by the position detector.
However, in the above shape measuring apparatuses for eyeglasses, a turning angle by the turning section is approximately 20 degrees at most. Therefore, it is difficult to measure the shape of an eyeglass frame which is highly-curved such as wraparound eyeglasses worn by athletes, for example.
Moreover, it is difficult for the shape measuring apparatus for eyeglasses to accurately measure a contour shape of the eyeglass frame which exceeds a base curve of 8, therefore a distance between geometric centers of each lens frame of the eyeglass frame is not obtained.
In addition, an eyeglass frame generally has a first lens frame and a second lens frame at the right and left, and a bridge which connects the first and the second lens frames. The eyeglass frame is manufactured symmetrically centering on the center of the bridge.
However, actual shapes and sizes of a first lens and a second lens which respectively fit in the first lens frame and the second lens frame are often slightly different from each other. If shape measuring data of one lens (for example, the first lens) is used for a fabrication of the other lens (for example, the second lens), these lenses do not often smoothly fit in the lens frames.
In a case as described above, an adjustment by hand is needed afterward, that is, an additional fabrication is needed. In some cases where the adjustment does not work properly and so on, there is a possibility that a new fabrication is needed.